The discharge or outlet ends of irrigation pipe are required to be periodically closed off and opened to control the flow of water therethrough. Such measures must be cheap, easily obtained and must not add significantly to the weight of the irrigation apparatus. This eliminates the integration of valves into the pipe itself.
Pipeline closures have been effected in the past. U.S. Pat. No. 2,526,238 to Kendall has a hollow cylindrical end cap which fits over the open end of a pipe of circular ring form with the cylindrical cap having an integral, vertical end wall which closes off the open end of the pipe. Means are provided for locking the end cap to the open end of the pipe. A slit ring coupled by diametrically opposite arms to the cap forms a collar which may be tightly drawn down about the pipe by rotation of clamping bolts through lugs having tapped bores. The clamping bolt has left hand and right hand threads over portions from its middle point towards a handle with the opposite direction threads being threaded to respective lug bores.
End closure retainers for holding stoppers within openings of cylindrical structures such as bottles and adapted to maintain corks within such bottle necks are found within U.S. Pat. Nos. 205,011, 337,202, 363,870, 511,645 and 1,292,919.
While patents directed to bottle cork holding clamps, bottle stopper retainers and the like may suggest certain approaches to maintaining bottle stoppers or corks in position, the particular problem at hand requires a mechanism which is lightweight, which has high strength and which is adapted particularly to maintaining a cylindrical plug axially inserted within the interior of an irrigation pipe at its outlet end. Such device must be capable of maintaining plug closure of the open end of the irrigation pipe, irrespective of the forces developed by water under some pressure interior of the pipe, trying to force the end plug or closure from that closed off pipe end. Additionally, the mechanism must be readily removable from the pipe both for quick closure of the pipe end or opening of the same while permitting the mechanism to be readily manually carried over some distances to and from the irrigation pipe itself.
It is therefore a primary object of the present invention to provide an improved lightweight, readily removable, high strength, low cost pipe clip in the form of an open frame structure, which may be readily coupled to the open end of an irrigation pipe, which eliminates the necessity for squeezing down a retainer ring about the periphery of the irrigation pipe to lock the clip to the pipe itself, and which is particularly adapted to belt end irrigation pipes.